Topologically Protected Complete Polarization Conversion
Topologically Protected Complete Polarization Conversion
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DOI：
10.1103/physrevlett.119.167401
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发表时间：
2017-10-18
影响因子：
8.6
通讯作者：
Fan, Shanhui
中科院分区：
文献类型：
--
作者：
Guo, Yu;Xiao, Meng;Fan, Shanhui
我们考虑当光从光子晶体板反射时线性偏振之间的转换过程。我们观察到，在很宽的频率范围内，可以在孤立的波矢量处找到完整的偏振转换。此外，这种效应是拓扑性的：复反射系数在波矢量空间中具有非零缠绕数。我们还表明，该系统中连续体中的束缚态的波矢位于临界耦合曲线上，该曲线定义了完全偏振转换的条件。我们的工作指出使用拓扑光子学概念来控制偏振，并建议探索散射矩阵的拓扑特性作为创建稳健光学器件的途径。
We consider the process of conversion between linear polarizations as light is reflected from a photonic crystal slab. We observe that, over a wide range of frequencies, complete polarization conversion can be found at isolated wave vectors. Moreover, such an effect is topological: the complex reflection coefficients have a nonzero winding number in the wave vector space. We also show that bound states in continuum in this system have their wave vectors lying on the critical coupling curve that defines the condition for complete polarization conversion. Our work points to the use of topological photonics concepts for the control of polarization, and suggests the exploration of topological properties of scattering matrices as a route towards creating robust optical devices.